Saliva is a reliable, non-invasive specimen for SARS-CoV-2 detection

Abstract

Background Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the cause of Coronavirus Disease 2019 (COVID-19). Although Real Time Reverse Transcription Polymerase Chain Reaction (qRT-PCR) of respiratory specimens is the gold standard test for detection of SARS-CoV-2 infection, collecting nasopharyngeal swabs causes discomfort to patients and may represent considerable risk for healthcare workers. The use of saliva as a diagnostic sample has several advantages. Objectives The aim of this study was to validate the use of saliva as a biological sample for diagnosis of COVID-19. Methods This study was conducted at Infectious Diseases Research Laboratory (LAPI), in Salvador, Brazil. Participants presenting with signs/symptoms suggesting SARS-CoV-2 infection underwent a nasopharyngeal swab (NPS) and/or oropharyngeal swab (OPS), and saliva collection. Saliva samples were diluted in PBS, followed by RNA isolation and RT-Real Time PCR for SARS-CoV-2. Results of conventional vs saliva samples testing were compared. Statistical analyses were performed using Statistical Package for the Social Sciences software (SPSS) version 18.0. Results One hundred fifty-five participants were recruited and samples pairs of NPS/OPS and saliva were collected. The sensitivity and specificity of RT-PCR using saliva samples were 94.4% (95% CI 86.4–97.8) and 97.62% (95% CI 91.7–99.3), respectively. There was an overall high agreement (96.1%) between the two tests. Conclusions Use of self-collected saliva samples is an easy, convenient, and low-cost alternative to conventional NP swab-based molecular tests. These results may allow a broader use of molecular tests for management of COVID19 pandemic, especially in resources-limited settings.

Comparing saliva and nasopharyngeal swab specimens in the detection of COVID-19: A systematic review and meta-analysis

“…2 provide general information on the selected articles. 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 It needs to be clarified that in the studies by Jamal et al and Williams et al T (total number of patients participating in the study) in the meta-analysis and data visualisation is, in fact, the number of the participating patients which were considered in the final analysis for detection of COVID-19. 9 , 14 In addition, due to unclear data on 8 patients in the study by Procop et al, 8 specimens were excluded from the final comparative analysis; therefore, the rest of participating patients were included in the meta-analysis and Fig.…”

Validation of the GeneXpert Xpress SARS-CoV-2 PCR assay using saliva as biological specimen

“…Results of conventional NPS and/or OPS versus saliva samples testing were compared by performing qRT-Real Time PCR assay. 6 There was an overall high agreement (96.1%) between the two tests. In the present study, we detected an overall equivalence between results of qRT-Real Time PCR and Xpert Xpress SARS-CoV-2 assay.…”

“…Recent studies have shown a high detection rate using saliva/oral fluids as specimens for laboratory detection of SARS-CoV-2. 3 , 4 , 5 , 6 The use of saliva as biological sample has several advantages, such as easy self-collection even at home, and no need of trained personnel for sample collection. In addition, saliva collection is much more comfortable for the patient than NPS or OPS procedures.…”

“…We used 40 saliva samples collected during June and July 2020, from a previous validation study from our group. 6 Saliva samples from symptomatic participants were collected into 30 mL sterile urine cups, and kept at −80 °C until testing. Participants were instructed to repeatedly spit until approximately 2 mL of sample was obtained, thus avoiding mucous secretions from oropharynx or lower respiratory tract (i.e., sputum).…”

SARS-CoV-2 in Mexico: Beyond Detection Methods, Scope and Limitations

“…As an alternative, the use of saliva as a less invasive specimen for the detection of SARS-CoV-2 by RT-qPCR has been studied [ 14 , 15 ]. Despite the fact that many studies agree with the similarity of viral detection by PCR in oropharyngeal and nasopharyngeal swabs with saliva [ 16 ], in Mexico, its use as a specimen for the diagnosis of COVID-19 by RT-qPCR is not authorized.…”